1. Field of the Invention
This invention relates to a method and apparatus for severing roots and leaves of bean sprouts.
2. Description of the Related Art
For example, a growing container of about 1xc3x972xc3x971.5 (-meters) is generally used in a growing method for mass-production of bean sprouts. A large quantity of seed is put into the growing container, and water is sprinkled over the seed in a suitable manner. As a result, the seed is germinated such that bean sprouts are grown up. Under the present circumstances, a large amount of bean spouts are piled up into several layers in the growing container. Upper layers of bean sprouts are gradually raised up by the lower layers of bean sprouts with growth of the latter layers. Bean sprouts grow up to have a length (6 to 8 cm) suitable to be eaten in about five to eight days after germination. At this stage of growth, the bean sprouts are taken out of the growing container and washed in water. The bean sprouts are then packed or bagged by a predetermined amount and shipped or transported to supermarkets and the like.
The bean sprouts sold as described above retain roots and leaves, which degrade an appearance of bean sprouts and diminish our appetite. Accordingly, roots and leaves are severed from bean sprouts with a kitchen knife in the Chinese cooking so that the bean sprouts including only sprouts are used in the Chinese cooking. Roots and leaves are conventionally severed with a kitchen knife manually. However, a severing work is time-consuming and troublesome.
In view of the foregoing problem, the prior art has proposed a method of obtaining bean sprouts including only sprouts. In the proposed method, as in a method of growing fresh radish sprout, a growing mat is used so that locations of roots are made uniform. Sprouts of a number of bean sprouts having grown thick on the growing mat are gripped by hand so that leaves of the bean sprouts are collectively severed with a kitchen knife, and the growing mat on which roots of the bean sprouts have grown thick is also severed, during harvest or cooking, whereby roots of all the bean sprouts are collectively severed.
In the foregoing method, however, the roots and leaves need to be manually severed with a knife. Thus, the problem of troublesome severing work with the kitchen knife cannot completely be solved. Moreover, the growing method in which the growing mat etc. is used to make the locations of roots uniform has a lower productivity and necessitates higher production cost as compared with a conventional growing method in which the bean sprouts are stacked into layers in the growing container. Furthermore, the sprout of the bean sprout become thinner such that the appearance of the bean sprout is degraded or the bean sprout is less appetizing.
Therefore, an object of the present invention is to provide a method and apparatus for severing roots and leaves of bean sprouts, which method and apparatus can automate a work for severing roots and leaves of bean sprouts mass-produced in a growing method similar to the conventional method.
To achieve the object, the present invention provides a method of severing roots and leaves of bean sprouts, comprising the step of disposing a cylindrical case on a severing table having a number of severing slits each of which has such a width that a root and leaf of a bean sprout are allowed to fall thereinto. The cylindrical case encloses bean sprouts in a standing state. The roots may be located higher or lower than the leaves and vice versa. When water is sprinkled or air is caused to blow from over the cylindrical case, the water or air flows downward in the cylindrical case, further flowing downward through the severing slit. As the result of such flow of water or air, the root or leaf of the bean sprout in the cylindrical case fall into the severing slit. A first severing work is carried out in which the roots or leaves fallen into the severing slit are severed. Thereafter, the cylindrical case is inverted upside down so that the bean sprouts in the cylindrical case are inverted upside down. A second severing work is carried out in which the downward roots or leaves of the bean sprouts are severed in the same manner as in the first severing work. Consequently, the roots and leaves severing work can be automated while the damage to the bean sprouts can be reduced as much as possible. Moreover, since the roots and leaves need not positionally correspond with each other, bean sprouts mass-produced in a growing method similar to the conventional method and having thick sprouts can be used, and bean sprouts which have a good appearance and are appetizing can be produced at low costs.
Either cylindrical case or severing table may be moved. In a preferred form, the cylindrical case has a lower edge and the severing slit has an edge, and the cylindrical case is moved along an upper face of the severing table so that the roots and leaves of the bean sprouts fallen in the severing slit are held between the lower edge of the cylindrical case and the edge of the severing table thereby to be severed. Since the lower edge of the cylindrical case serves as a cutter blade, no separate cutter blade is required. Consequently, since a severing structure is simplified, the equipment cost can be reduced. Moreover, the movement of the cylindrical case can result in continuous and efficient severing of the roots and leaves of the bean sprouts and conveyance of bean sprouts.
When the edge (corresponding to a cutter blade) of the cylindrical case is parallel with the severing slit, the roots of the bean sprouts need to be simultaneously held between the lower edge of the cylindrical case and the edge of the severing table thereby to be severed. In this case, a load applied to a drive motor for the cylindrical case in the severing is increased. Accordingly, a driving force of the drive motor needs to be increased. This would, however, result in an increase in the size of the drive motor and an increase in the electric power consumption.
As a countermeasure, for example, the edge of the severing slit or the edge of the cylindrical case may be inclined relative to a moving direction of the cylindrical case. Alternatively, the edge of the severing slit or the edge of the cylindrical case may be formed zigzag such that the severing slits and the edges of the cylindrical cases are located diagonally relative to each other. Accordingly, when passing the severing slit, each edge of the cylindrical case diagonally intersects the edge of the severing slit, and a point of intersection moves along the edge of the severing slit with movement of the cylindrical cases. As a result, since the roots and leaves in the severing slit are gradually severed, they can easily be severed and the driving force of the drive motor for the cylindrical case can be rendered smaller. Consequently, the size of the drive motor can be reduced, and the electric power consumption can be reduced.
In another preferred form, the cylindrical case has an opening with dimensions smaller than a length of the bean sprout, and the bean sprouts conveyed on a conveyor are caused to fall into the cylindrical case so that the bean sprouts are enclosed in the standing state in the cylindrical case. In other words, when the dimensions of the opening of the cylindrical case are smaller than the length of the bean sprout, the bean sprouts falling from the conveyor into the cylindrical case is prevented from lying sideways in the cylindrical case, so that the bean sprouts are enclosed in the cylindrical case with either the root or the leaf standing. Consequently, the work for enclosing the bean sprouts in the cylindrical case can be automated.
In further another preferred form, the conveyor comprises a vibrating or oscillating conveyor conveying the bean sprouts by means of vibration or oscillation, although a belt conveyor is used. When the bean sprouts form a large mass on the belt conveyor, there is a possibility that the large mass may fall into the cylindrical case and close the upper opening of the case. As a result, the bean sprouts may not be enclosed in the standing state in the cylindrical case. Accordingly, when the bean sprouts are conveyed on the belt conveyor, a small amount of the bean sprouts needs to be spread over the belt conveyor so as to be prevented from forming into a large mass.
On the other hand, when a vibrating or oscillating conveyor is used and the bean sprouts supplied onto the vibrating or oscillating conveyor form a large mass, the mass can be taken to pieces during conveyance by the vibration caused by the vibrating conveyor. Accordingly, the bean sprouts can be prevented from falling in masses from the supplying conveyor into the cylindrical cases and caused to continuously fall into the cylindrical case bit by bit. Consequently, the bean sprouts can easily be enclosed in the standing state in the cylindrical case.
In further another preferred form, two severing tables are disposed above and below, and a number of the cylindrical cases are connected into a belt shape and driven to be moved along upper sides of the upper and lower severing tables. Furthermore, the cylindrical cases are moved from an end of the upper severing table toward an end of the lower severing table so as to make a generally semicircular trajectory so that the cylindrical cases are inverted upside down, and two drop preventing covers are provided along outer and inner circumferential sides of the semicircular trajectory respectively, the drop preventing covers preventing the bean sprout from dropping out of the cylindrical case. Consequently, a sequence of the first severing, the upside-down inverting of cylindrical case, and the second severing can be carried out continuously and smoothly by the rotation of an apparatus comprising a number of the cylindrical cases connected into a general belt shape. Further, the apparatus can be rendered smaller since the two severing tables are disposed above and below.
The severing table may be made by forming severing slits in a metal plate by means of punching. Alternatively, the severing table may comprise a number of bar-shaped members formed with respective edges for severing the roots and leaves of the bean sprouts. In this case, the bar-shaped members are arranged in parallel with one another with a clearance between each bar-shaped member and an adjacent bar-shaped member, the clearance having a width allowing the roots and leaves of the bean sprouts to fall thereinto and serving as the severing slits. Consequently, the width between each bar-shaped member and the adjacent one can be adjusted according to the type or size of the bean sprouts, whereby the clearance between the bar-shaped members can easily be adjusted.